Hitherto, a terminal for electrical connection comprises a base material made of a copper-based alloy and a plated layer which is coated on the base material and made of tin (Sn), a solder, nickel (Ni), gold (Au), silver (Ag) or the like selected according to service conditions.
For example, tin which is cheap is plated on the terminal for electrical connection to improve corrosion resistance of the terminal. Gold which is hardly oxidized is plated on the terminal for electrical connection, when a slight electrical current passes through the terminal for electrical connection. It is essential to plate gold, particularly in the case of the terminal which is used in a severe environment, for example, in an outdoor or under a hood of automobile in which a slight electrical current is treated.
However, the tin-plating has such a problem that it has poor reliability since the terminal for electrical connection may be corroded when used for a long time. The gold-plating has such problems that it is expensive and that it has inferior mechanical properties such as abrasion resistance.